Root Z Diplomacy (cb60)

by Phil Creed, Tom Hyer, Mark Nelson

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In essence, the Root Z variant allows seven players to control a power on each of two identical Diplomacy boards, with access between the two boards by moving across any border of the border line running from Mar-Pie in the north to Mao-Naf in the south.

The effect is quite different from simply imposing one board on top of another, as in “parallel dimensions” where say, Bur1 accesses Bur2 and Bud1 accesses Bud2.  A better analogy might be an interlocking spiral (joined at the ends).  As the designers say below, the talk of “two boards” is confusing: this is really *one* board!

Another way for the non-mathematicians (like myself) to view it is as follows: Picture a stick with one end placed at Switzerland and running to the Mao-Naf border.  Now, holding the Switzerland end at Switzerland, swing the other end toward Italy, and around the board to France.

When reaching the Mao-Naf border again, the stick now transports to the same place on Map 2.  Again, move the stick around the board, and when reaching the Mao-Naf border a second time, the stick returns to the starting place on Map 1.  As described before, the effect is that of a spiral joined at the ends, creating a single board!

((These rules are based upon an original design by Phil Creed and Mark Nelson which were posted to in April (or was it May?) 1993. This new set of rules is based upon the extensive discussion about the rules and has been written by Phil Creed, Tom Hyer and Mark Nelson. We would like to thank everyone who took part in the discussion, in particular: Rick Desper, Gary Duke, Lars Henrik Mathiesen, Robert Rehbold, Joel Evan Rosenberg and Frederick Scott. This revised set of rules is dated 7th June 1993.))

(1.0) Introduction

The idea for this variant comes from the mathematical concept of a cut in the complex plane.  When applied to two diplomacy boards this creates a link between the two boards.  Locally the cut appears to have no effect because a unit “views” exactly the same provinces across the cut line as in standard diplomacy, however a unit trying to move across the cut line moves from one board to the other board.

Natural extensions of the idea introduced in this variant would be to have one, or more, cuts on two, or more, boards.


(1.0) The 1971 rules of diplomacy apply except where modified below.

(2.0) There are two boards, denoted by “1” or “2” appended to country or province names.  There are seven players, each of whom controls two powers; see rule (3).

(2.1) In adjudications units are labeled in the format iJK where i (i=1 or 2) is the board on which the unit was built, J (J =A, E, F, G, I, R or T)  is the country which built the unit and K (K =A or F) is the unit type. eg if France on board one builds A(Par) this is denoted 1FA(Par), if Germany builds F(Kie) on board two this is 2GF(Kie).

(3.0) The map described above contains two disconnected “mega-zones” of sea provinces (for example, no fleet can move from Bar1 to Eas1). Each player must control one power adjacent to each “mega-zone”.  When signing onto the waiting list, a player shall enter two preference lists, one corresponding to each “mega-zone”.  Such a list might look like:  E1,G1,F1,T2,A2,R1,I2; T1,A1,G2,F2,E2,I2,R2.  (This particular list is strongly anti-R1, as the top choices on each list are adjacent to R1.)

(3.1) For purposes of allocation of countries, R1 shall be considered to adjoin the mega-zone containing Bar1, not that containing Bla1.

(3.2) No player may control A/R or R/T.  (Mark:  alternatively, we could count R1 in the mega-zone adjoining Bla1 and Bar2, and forbid E/R and G/R; the effect is similar.)

(4.0) There is a cut along the two boards as follows (the cut is identical on both boards): Along the Mar-Pie border, the Mar-GoL border, the Spa-GoL border, the Spa-Wes border, the MAO-Wes border, and the MAO-NAf border where the cuts hits the edge of the board.

(4.1) Each province is labeled according to the number of the board it is on; e.g., Bur1 is not to be confused with Bur2.

(4.2) The cut has no effect *except* that a unit moving across the cut moves to the corresponding province on the other board; e.g, Mar1 is adjacent to Bur1, GAS1, Spa1, GoL2, Pie2.

Locally, the adjudication of orders proceeds as if the pieces involved were on a single board (since the placement of the cut is purely conventional, we can imagine performing the adjudication on a board where the cut is far from the area involved).  Thus A Mar1 S F GoL2-Pie2 has the same effect as A Mar S F GoL-Pie would be expected to have.

(4.3) Provinces on different board should be treated as distinct with respect to movement.  Specifically, A Mar1-Pie2 does not stand out F Pie1-Mar2, as the
two actions take place in different sectors of the board.

(4.4) Convoys: Convoys across the cut are allowed; e.g., F Wes2 C A Spa1-Tun2.

(4.5) Supports across the cut are valid; see (4.2).

(5.0) A centre captured on board 1(2) by a unit built on board 2(1) is owned by nation on board 2(1).

(5.1) Although there are 7 players there are 14 distinct powers in this game. France1 can attack France2, France1 can dislodge France2 units and France1 can
capture France2 centres.  If your powers are Austria1 and England2 then Austria1 can attack England2, can dislodge England2 units and capture England2

(6.0) The victory condition is 28 centres, owned by a combination of a player’s two powers.  If two players reach this target simultaneously the player with the most centres wins.  If they have the same number of centres then they share a two-way draw.

(7.0) OPTIONAL RULE: This variant could be played as a 14-player game rather than a 7-player game.  In this case the victory criterion should be reduced to 18 centres.  The designers believe that the 7-player game is better.


The following table shows which combinations of powers are not allowed by rules (3.1)-(3.4)



This is an attempt to show the relationships between the powers in this game.

In regular diplomacy the relationship between the powers can be represented by:

O = pole at Switzerland

 In this variant the effect of the cut is to link the two boards together as outlined below:

O = pole at Switzerland

Here we have cut map one open, then compressed it to cover 180 degrees around Switzerland, instead of 360. Map two is formed in identical manner, then glued to map one along the cut.

This map shows that our earlier talk of “two boards” was slightly misleading.  What we really have is one topologically confusing, yet still planar, map!  The above map readily shows that a 14-player version would work. We dislike it because there wouldn’t be very much contact between the players.